Ions are atoms or groups of atoms that have either lost or gained electrons so they have a positive or negative charge.
Atoms make up all matter around us, they are the smallest part of all things. Atoms in the periodic table all have different numbers of protons and are known as elements and they can be combined to make compounds and molecules
Bonding describes how metallic and non metallic elements of the periodic table exist as elements or combined together to form new compounds with different properties.
Metallic bonding is the bonding found in metals, positive metal ions surrounded by a sea of delocalized electrons.
Ionic bonding is the bonding formed when metals and non metals transfer electrons creating oppositely charged ions.
Ionic compounds have a number of properties due to their bonding, they are brittle, non conductive as a solid and have high melting and boiling points.
Radioactivity is a property of a number of elements in the periodic table where their nuclei break down and release particles such as alpha, beta and gamma particles.
The Group 2 Alkaline earth metals are the 2nd group in the periodic table and are just before the transition metals. They are all similar in their color of silvery/white metals and react with water to form alkaline solutions. They are however not as reactive as the group 1 metals as they have 2 valence electrons instead of 1.
The Halogens in Group 17 are non metal elements that are diatomic and simple covalently bonded. They decrease in reactivity down the group but increase in their melting and boiling points.